3. The planet Earth
The Earth is a very special planet. It is the only planet that is able to support life, because it has some unique characteristics:
- Its atmosphere contains oxygen (O2) and
carbon dioxide (CO2) that are essential
gases of photosynthesis and respiration.
- The temperature on its surface is about
15ºC, because of the distance from the Sun
and the composition of the atmosphere.
- Water exists as ice, liquid water
and water vapour. It makes
the water cycle possible.
- The Earth has a magnetic field
which protects the surface
from solar radiation.
- The Moon is a very large satellite
that is responsible for tides.
- It has geological activity
(volcanos, earthquakes, etc)
READING ACTIVITIES
After reading the text, copy and answer the following questions into your notebook:
Remember: you must make complete sentences.
3.1. Mark the characteristics that make the Earth a habitable planet.
Then listen and indicate which of them are
mentioned.
a. There is water in the three states of matter.
b. It is near the Sun.
c. Most of the planet is covered by water.
d. The atmosphere is rich in nitrogen.
e. There are night and day, and seasons.
f. The temperature is about 15ºC
g. It is very big.
h. There is solar radiation that gives light and heat.
i. It has a magnetic field that protects it.
j. It has an atmosphere with oxygen and carbon dioxide.
3.2. The distance of Venus and Mars from the Sun makes life possible ,
but neither have living beings. Look the table that summarises
the characteristics of both planets in the activity 2.2.
and explain why they do not support life.
Now,
check
your
answers!